Flying for a low coast carrier, we do the load sheet and trim sheet for every flight. With practice, it becomes easily done. Ground ops just gives you the number of passengers (adults, children, infants) and the total baggage/cargo weight and in which cargo hold(s) they are in. Fuel load is selected by the crew and then rest is just simple calculation and plotting.
Yes, a specific question would be good or if you really want detailed info, message me if you want reference material posted to you.